GUI: Improve Mass Add dialog
|Reported by:||fingolfin||Owned by:||sev-|
1) The user should see a list of games that will be added. This could be realized by adding a ListWidget to the progress dialog, which gets updated in real-time, too. Shouldn't be very hard to implement.
2) After adding new games, scroll to and select the "first" one (or, at least any of them).
Ticket imported from: #2707442. Ticket imported from: feature-requests/505.